A verb is a word which refers to an action, whether tangible or abstract. Here are some examples of verbs:
to swim
to undulate
to maraud
to bake
to chicken out
to ooze
Verbs are almost always being ‘done’ by someone or something, and in German they change depending on who, and how many people, is/are doing the verb. We call these changes conjugations. However, when we are using a verb without anyone specific carrying out that action, we put it in the ‘infinitive’, meaning the completely abstract and depersonalised version of that verb. In English, we make the infinitive with ‘to -‘ and then the unconjugated verb, but in German we just use the form of the verb with -en at the end. For example:
laufen
springen
kauen
schnurren
tanzen
und so weiter…